"President Duterte specifically asked PM O'Neill to help the Philippine tuna industry by allowing Filipino fishing companies to continue bringing part of their catch to processing plants in General Santos City," Piñol said in a statement.

Papua New Guinea, one of the richest fishing grounds for tuna, signed new regulations that require all foreign fishing companies to process their tuna catch within the country, Piñol said.

Duterte told O'Neill that "many of (the Filipino) people in the south will lose jobs and this is where we are grappling with the problem of insurgency and terrorism," Piñol said.

In exchange, Duterte promised to help develop Papua New Guinea's rice and coconut industry as O'Neill's country "imports 100% of its rice requirements," the Filipino agriculture chief said.

Piñol said O'Neill "promised to review the new fishing regulations and promised consultations with the Filipino investors in his country."

Duterte and O'Neill's exchange happened during the Philippines-Papua New Guinea bilateral meeting on the sidelines of the Asia-Pacific Economic Cooperation Summit in Vietnam.